共查询到20条相似文献,搜索用时 31 毫秒
1.
Homogeneous polymerization of p-diethynylbenzene initiated by nickel acetylide Ni(C ≡ C C_6H_4 C ≡ CH)_2(PPh_3)_2has been investigated in terms of different solvents, addition agents, atmosphere gases, catalyst concentrations, monomerconcentrations and polymerization temperatures. The yield and catalytic efficiency approach 88% and 11. 1 kg polymer/molNi, respectively, under the optimum conditions: [cat] = 0.01 mol/L, [M] = 1.0 mol/L, NEt_3/cat (mol ratio) = 3~5, 1,4-dioxane/toluene (volume ratio) = 1 and T = 25℃ for 5 h. The polymerization rate equation can be expressed as R_p =k_p[M][cat]~2, where k_p= 0.47 L~2. mol~(-2)·S~(-1) (25℃). The overall polymerization activation energy was found to be203 kJ·mol~(-1). Poly(p-diethynylbenzene) so obtained is soluble in THF, CHCl_3 and toluene with weight-average molecularweights as high as 27, 100 and a rich-trans extended π-conjugated polyene chain structure with pendent groups ofp-C_6H_4C≡CH. 相似文献
2.
Reaction of Ru 4(CO) 13( 3-PPh) (1) with the 1,3,5-hexatriyne Me 3SiCCCCC CSiMe 3 under mild thermal conditions affords initially Ru 4(CO) 10(-CO) 2{ 4- 1, 1, 2-P(Ph)C(CCSiMe 3)C(CCSiMe 3) (2), via the facile formation of a P–C bond in a manner similar to that demonstrated previously with alkynes and diynes. The 62-CVE cluster 2 readily decarbonylates to give crystallographically characterised Ru 4(CO) 10(-CO)( 4-PPh){ 4- 1, 1, 2, 2-Me 3SiCCC 2CCSiMe 3} (3). Attempts to further incorporate the pendant alkyne moieties in 3 into the Ru 4 coordination environment were partially successful with Ru 4(CO) 10( 4-PPh)( 4- 1, 1, 3, 3-RC 4R') (4, R/R'=SiMe 3/CCSiMe 3) being formed as a minor product together with the unusual toluene coordinated species Ru 4(CO) 7( 6-C 6H 5Me)( 4-PPh)( 4- 1, 1, 3, 3-Me 3SiC 4CCSiMe 4) (5). Cluster 3 reacts with an excess of Me 3SiCCCCCCSiMe 3 to give the open chain cluster Ru 4(CO) 9( 3-PPh){ 4- 2, 2, 4, 4,-C 4(CCSiMe 3)(SiMe 3)C 4(CCSiMe 3) 3} (6). 相似文献
3.
IR and NMR data showed that the ionic complex Pd 2(CHCC 6H 5) 2(C 5H 7O 2) 3(BF 3) 2BF 4 isolated in the reaction Pd(Acac) 2 + PA + 5BF 3OEt 2 (Acac is C 5H 7O 2, PA is phenylacetylene) is an adduct of two complexes, namely, (Acac)PdBF 4 and [(PA) 2Pd(C 3-Acac · BF 3)] +(Acac · BF 3) – (coordinatively unsaturated). On dissolution in deuteroacetone or deuteromethanol, the [(Acac)PdF 2BF 2Pd(C 3-Acac · BF 3)(PA) 2] +(Acac · BF 3) – adduct decomposed to Pd(Acac) 2, 2BF 3 · L (L = (CD 3) 2CO, CD 3OD) and the [L(PA) 2Pd(C 3-Acac] +BF 4
– complex. 相似文献
4.
Hydrolysis of dicopper diacetylide Cu-C≡C-C≡C-Cu in HCl solution yields diacetylene as major product together with a mixture of polyynes and minor amounts of carbonaceous matter. After I month ageing the main hydrolysis product from dicopper diacetylide is insoluble carbonaceous matter (23.47% by weight) together with diacetylene and its superior homologues (polyynes formed from solid state oxidative coupling reaction) which have been qualitatively and quantitatively identified by electronic spectroscopy. Similar behaviour and results are observed on dicoppper acetylide Cu-C≡C-Cu. In the carbonaceous insoluble matter recovered after hydrolysis, the presence of carbyne was detected by FT-IR spectroscopy.Dicopper acetylide Cu-C≡C-C≡C-Cu and dicopper acetylide, irrespective for the degree of oxidation reached in air, undergo a controlled thermal decomposition by heating under reduced pressure yielding in few seconds carbyne and copper(I) oxide, both identified by FT-IR spectroscopy. 相似文献
5.
This paper presents a new convenient route to prepare osmafuran starting from readily accessible HC≡CCH(OH)C≡CH and OsHCl(CO)(PPh3)3. Treatment of a solution of OsHCl(CO)(PPh3)3 in dichloromethane with HC≡CCH(OH)C≡CH, followed by the addition of acetic acid, produced osmafuran [Os(CHC(PPh3)CO(CH2CH3))Cl(CO)(PPh3)2]Cl (2). 2 has been isolated in good yield and fully characterized. 1H and 13C NMR spectra show the characteristic downfield chemical shifts of the ring hydrogen and carbon atoms. NMR and X-ray diffraction data provide strong evidence for the aromatic nature of 2. Probably due to the effect of the phosphonium substituent, 2 exhibits remarkable thermal stability, air stability and lower reactivity. 相似文献
6.
Dicopper diacetylide Cu-C≡C-C≡C-Cu, prepared from butadiyne has been studied by FT-IR spectroscopy in comparison to dicopper acetylide Cu-C≡C-Cu. Upon ageing by exposure to air at room temperature, Cu-C≡C-Cu has been transformed into Cu-C≡C-C≡C-Cu as demonstrated by FT-IR spectroscopy and this compound is further transformed on standing in air. A special kind of solid state oxidative coupling reaction occurs so that polyynes chains are formed in these aged solids. It is shown that the FT-IR spectrum of copper acetylide prepared from ammonia solutions of Cu + and Cu 2+ ions is comparable to that of air oxidized Cu-C≡C-Cu (and Cu-C≡C-C≡C-Cu) prepared exclusively from Cu + ions in presence of a reducing agent demonstrating that Cu 2+ ions display the same oxidizing effect as oxygen causing coupling reactions in solution and producing Cu-C≡C-C≡C-Cu.Cu-C≡C-Cu oxidized at 60–70°C with CuCl 2 produces a product which could be formulated as Cu(C≡C) 20Cu; FT-IR absorption at 1950 cm −1 could suggest the presence of cumulenic carbon chain although acetylenic carbon chains cannot be excluded completely. 相似文献
7.
New tungsten carbyne complexes (Bu tO) 3WC—SiPh 3, [(Bu tO) 3WC] 2SiPh 2, [(Bu tO) 3WC] 2GePh 2, and [(Bu tO) 3WC] 2SnPh 2 were prepared by the reactions of (Bu t) 6W 2 with Ph 3SiCC—Pr or Ph 2E(CC—Pr) 2 (E = Si, Ge, Sn) in individual crystalline form in 48—80% yields. The structures of both the (Bu tO) 3WC—GePh 3 and (Bu tO) 3WC—SnPh 3 compounds synthesized earlier and the new complexes were established by X-ray diffraction analysis. 相似文献
8.
采用 B3LYP和 CCSD(T)方法对 R-C≡ P(R=-BH2, -CH3,-NH2, -OH)体系进行了理论研究 .结果表明,含 C≡ P三键的异构体 BH2-C≡ P和 CH3-C≡ P在各自的体系中分别是热力学最稳定的结构 .而在 HO-C≡ P和 NH2-C≡ P体系中,热力学最稳定的结构却是 H-P=C=O和含 C≡ N三键的 N≡ C-PH2.动力学理论研究表明,没有相关实验研究的 R-C≡ P(R=-BH2,NH2)体系中共有 5种异构体是动力学稳定的 .在 HO-C≡ P体系的 2种动力学稳定的异构体中, H-P=C=O连接方式的异构体已被实验所证实,而另外一种 HO-C≡ P连接方式的异构体的动力学稳定性较高,实验中可以观察到 .对于 CH3C≡ P体系,研究所预示的 2种动力学稳定的异构体中 CH3-C≡ P已被实验证实,从理论上推测另一种动力学稳定性较高的异构体 HC≡ C-PH2在实验中也可以检测到. 相似文献
9.
The effect of the Grignard compounds (EtMgBr, PhMgBr, t-BuMgCl, cyclo-C 6H 1
1MgBr, and PhCÍÄCMgBr) on the isomerization of HCÍÄCCH 2XMR 3 into R 3MCÍÄCCH 2XH (M = Si, Ge; X = O, S) was studied. The efficiency of the 1,4-(Xarr;Csp)-migration of the R 3M group was shown to depend on the nucleophilicity of the Grignard compound and nature of the MÄX bond. 相似文献
10.
室温下, 用Cp2ZrCl2 与LiC≡CPh反应, 合成了碳碳偶合反应的Zr(Ⅱ)阴离子中间体Li[Cp2Zr(C≡CPh)(η2:1,2-PhC2C≡CPh)]. 用元素分析、核磁共振谱和红外光谱对配合物进行了表征, 配合物的晶体结构分析给出了两个炔烃之间碳碳偶合的证据. 用核磁共振谱初步探讨了合成反应机理. 相似文献
11.
We have determined the peritectic decomposition temperatures for YBa 2Cu 3O 7−x, EuBa 2Cu 3O 7−x and HoBa 2Cu 3O 7−x: they are 1030, 1060 and 980 °C respectively at P = 1 atm O 2. We have also determined the pressure-temperature behaviour of the orthorhombic-tetragonal transition in HoBa 2Cu 3O 7−x. Evidence of the possibility of improving the texture of these samples by partial melting and treatment in thermal gradient is also pointed out. 相似文献
12.
The vibrational overtone spectra of the acetylenic (Δυ = 4, 5) and methyl (Δυ = 5, 6) C-H stretch transitions of tert-butyl acetylene [(CH(3))(3)C-C≡C-H] were obtained using the phase shift cavity ring down (PS-CRD) technique at 295 K. The C-H stretch fundamental and overtone absorptions of the acetylenic (Δυ = 2 and 3) and methyl (Δυ = 2-4) C-H bonds have been obtained using a Fourier transform infrared and near-infrared spectrophotometer. Harmonic frequency ω(ν(1)) and anharmonicities x(ν(1)) and x(ν(1), ν(24)) are reported for the acetylenic C-H bond. Molecular orbital calculations of geometry and vibrational frequencies were performed. A harmonically coupled anharmonic oscillator (HCAO) model was used to determine the overtone energy levels and assign the absorption bands to vibrational transitions of methyl C-H bonds. Band strength values were obtained experimentally and compared with intensities calculated in terms of the HCAO model where only the C-H modes are considered. No adjustable parameters were used to get order of magnitude agreement with experimental intensities for all pure local mode C-H transitions. 相似文献
13.
The hydrogen-transfer reaction of W + NH(3) incorporates four possible diabatic reaction pathways along with septet, quintet, triplet, and singlet states. The intersystem crossings thus play an important role in the reaction mechanisms. In this work, ab initio and DFT methods are used to determine all possible intermediates, transition states, products, and intersystem crossing points as well as the spin-orbit couplings. The mechanism of hydrogen elimination is further revealed by the natural bond orbital analysis. From the rate constants yielded by a nonadiabatic transition state theory, we find that two intersystem crossings significantly change the reaction pathways. Finally, we suggest a feasible reaction pathway with exothermicity 72.8 kcal/mol, which is consistent with the experimental measurements. 相似文献
14.
The triply bonded heavier main-group compounds have a textbook trans-bent geometry, in contrast to a familiar linear form found for the lightest analogues. Strikingly, the unexpected linear group 13 E≡E triple bonds were herein found in the D4h-symmetry E 2Li 62+ clusters, and they possess a large barrier (>18.0 kcal/mol) towards the dissociation of Li +. The perfectly surrounded Li 4 motifs and two linear coordinated Li atoms strongly suppress the increasing nonbonded electron density of heavier E atoms, making two degenerate π bonds and one multi-center σ bond in linear heavier main-group triple bonds. The surrounding Li 6 motifs not only creates an effective electronic structure to form a linear E≡E triple bond, but the resulting electrostatic interactions account for the highly stable global E 2Li 62+ clusters. 相似文献
15.
Co_2(CO)_3中两个桥连的羰基很容易被一个炔键取代,生成羰基配合物(ROCH_2C)_2Co_2(CO)_6。此类配合物既可以催化炔烃三聚成苯,也可以作为炔烃的保护基团,还可以用它进行其它的合成。为此,我们用下述反应合成了这类配合物: 相似文献
16.
用含时密度泛函理论组合态求和方法研究实验合成的金配合物[Au(C≡C-4-LNO2)(PPh3),L=—C6H4(1),—C5H3N(2)]和自行设计的金配合物[Au(C≡C-4-C4H2N2NO2)(PPh3)L=—C4H2N2](3)的非线性光学性质.计算结果表明,3个配合物的二阶非线性性质变化规律为β1<β2<β3,与芳香性的变化规律正好相反.3个配合物的频率色散理论计算结果与实验观测值不符,暗示着晶体合成时的晶胞排列方式是影响体系宏观NLO性质的关键因素之一. 相似文献
17.
采用B3LYP和CCSD(T)方法对R-C≡P(R=-BH2, -CH3,-NH2, -OH)体系进行了理论研究.结果表明,含C≡P三键的异构体BH2-C≡P和CH3-C≡P在各自的体系中分别是热力学最稳定的结构.而在HO-C≡P和NH2-C≡P体系中,热力学最稳定的结构却是H-P=C=O和含C≡N三键的N≡C-PH2.动力学理论研究表明,没有相关实验研究的R-C≡P(R=-BH2, NH2)体系中共有5种异构体是动力学稳定的. 在HO-C≡P体系的2种动力学稳定的异构体中, H-P=C=O连接方式的异构体已被实验所证实,而另外一种HO-C≡P连接方式的异构体的动力学稳定性较高,实验中可以观察到.对于CH3C≡P体系,研究所预示的2种动力学稳定的异构体中CH3-C≡P已被实验证实,从理论上推测另一种动力学稳定性较高的异构体HC≡C-PH2在实验中也可以检测到. 相似文献
18.
Triosmium cluster Os 3(-H)(CO) 10(-- 2-CCC Me 2OMe) ( 1) was obtained by treating OS 3(-H)(-Cl)(CO) 10 with LiCCCMe 2OMe. The reaction of cluster 1 with HBF 4 · Et 2O at –60 °C leads to the cationic complex [Os 3(-H)(CO) 10(-,, 2-C=C=C Me 2)] +BF 4
– ( 2) with an allenylidene ligand. The s1H and 13C NMR spectra of complex 2 reveal the temperature dependence caused by migration of hydrocarbon and carbonyl ligands. Thermodynamic parameters were obtained for be exchange process of the allenylidene ligand.Translated from Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp, 2990–2992, December, 1996. 相似文献
19.
The new phosphines Ph 2PC 6H 4-4-CCR [R=SiMe 3 (1), H (2)] have been used to prepare Ru 3(CO) 9(Ph 2PC 6H 4-4-CCSiMe 3) 3 (4) and Ru(CCC 6H 4-4-PPh 2)(PPh 3) 2(-C 5H 5) (3), respectively, the latter with a pendent phosphine. Reaction of 4 with carbonate or fluoride affords Ru 3(CO) 9(Ph 2PC 6H 4-4-CCH) 3 (5) with pendent terminal alkynyl groups, the identity of which was confirmed by a structural study. Reaction of 5 with [Ru(NCMe)(PPh 3) 2(-C 5H 5)]PF 6 or reaction of Ru 3(CO) 12 with 3 gives Ru 3(CO) 9{(Ph 2PC 6H 4-4-CC)Ru(PPh 3) 2(-C 5H 5)} 3 (6). Complexes 3–6 have been studied by cyclic voltammetry. Proceeding from Ru 3(CO) 12 to 4 or 5 shifts the cluster-centred reduction to more negative potential and affords facile cluster-centred oxidation. Proceeding from 4/5 and 3 to 6 results in similarly-located cluster-centred reduction and peripheral ruthenium-centred oxidation, but results in a lack of observable cluster-centred oxidation. Crystal data for 5·C 6H 14: space group P¯1, a=12.760(1) Å, b=17.077(1) Å, c=17.924(2) Å, =108.656(5)°, =96.344(5)°, =93.523(5)°, V=3658.4(6) Å 3, Z=2, R=0.078, R w=0.105 for 5008 reflections [I>2.00(I)]. 相似文献
20.
The reactions of N≡W(O(t)Bu)(3) with the low-coordinate phosphorus compounds (Me(3)Si)(2)NP(NSiMe(3))(2) (I) and (Me(3)Si)(2)NPS(N(t)Bu) (II) were studied. Quantum chemical calculations were used to determine why Mo- and W-containing compounds with the same composition have different molecular structures. 相似文献
|